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Input Files; Acceptance Cones

It is necessary to describe the energy binning in a file. For a DC source analysis, this is PSRSPEC output file. In this case the bands will be defined when you run PSRSPEC. This will not be discussed here.

For a pulsar analysis, the energy bands are described in the ``cones.default'' file mentioned above. This file contains one line which tells how many energy bands are to be defined for class A events, and one line for each energy band. Each data line contains four pieces of information: a cone radius (in degrees), an upper energy limit, the empirical factor by which the effective area is to be divided, and the uncertainty in that factor. The first data line corresponds to class C events, and each subsequent line describes one of the class A bands. The upper energy limit in the class C line is actually the lower limit of the first class A band.

The choice of the proper acceptance cones is not well defined. For a weak source, the optimum choice is perhaps one which contains about 70% of the point spread function. For strong sources the cones should be larger. This question is irrelevant for DC analysis.

There is also a ``fit.default'' file that sets up some parameters for SPECNLYZ. This is an ordinary text file, and will be produced by a human. The file tells SPECNLYZ about the binning scheme, the form of the model, and some other parameters regarding the fit. The format of this file is rather fussy. It is recommended that users obtain a copy of the system default file and modify it.


next up previous
Next: Binning Up: How to Use SPECTRAL Previous: Program operation
CGRO SSC
1998-06-29